One of the most important issues in animal management is to determine the optimal captive environment for the physical and psychological well-being of a particular species. Estimates of well-being require data on behavior, physiology, trauma, health, and reproduction of animals kept under different conditions. The present project seeks to provide this information for species used as AIDS animal models, such as the chimpanzee (Pan troglodytes), rhesus macaque (Macaca mulatta), and pigtail macaque (M. nemestrina). Data collected on these three species under a variety of conditions with standardized protocols will provide a computerized data base (supplemented with a behavior manual and video material) that will enhance the ability of national breeding programs to justify existing housing conditions and/or provide an empirical basis for the design of future facilities. The project is also part of an ongoing effort to develop a new theoretical model of environmental effects on a ggressive behavior. Nonhuman primates have many checks on aggression, and appear to effectively cope with social tension related to crowding through appeasement and conflict resolution. In 1996 data were collected on 50 chimpanzees living in three different groups. Two groups live in outdoor compounds, the third is housed in indoor/outdoor runs. Data collection consisted of behavioral observation, injury checks, and fecal sampling. The latter was done to assess stress hormones such as cortisol. A collaboration grant from NATO will permit more intense coordination with a Dutch research team that is collecting identical information on a semi-free living group of chimpanzees.